Anti-piracy operatives have lost an edge over illegal downloaders of movies and software thanks to a new feature in BitTorrent.

BitTorrent creator Bram Cohen has eliminated the need for Web site hosting of centralised files, known as trackers, in the latest beta of the peer-to-peer software. These easily located files have been a key resource for anti-piracy units in identifying people downloading and sharing copyrighted material.

The change may cause problems in shutting down the illegal online distribution of software and content, according to the Business Software Alliance, an industry group.

"Currently, if a tracker site is shut down, many downloads are disrupted," said Tarun Sawney, BSA Asia antipiracy director. "So removing the trackers from the equation will obviously cause those of us on this side of the battle to regroup."

However, Sawney pointed out that BitTorrent files could still be identified. "BSA has traditionally sought the assistance of those hosting the actual pirated files. With or without the tracker sites, someone still hosts the infringing files," he said.

While BitTorrent's Cohen said the tracker removal feature is part of his ongoing effort to make publishing files online "painless and disruptively cheap", the move is only one of several designed to remove BitTorrent's dependence on centralised trackers.

Several of the Internet's largest tracker sites, such as SuprNova.org, were shut down in December following legal action by industry bodies including the Motion Picture Association of America. Similar legal action by Australia's music piracy investigations unit recently targeted local Internet provider Swiftel.

One development effort by Exeem, the group behind the once-popular SuprNova.org, aims to decentralise the BitTorrent protocol in the style of peer-to-peer networks like Kazaa, while a similar effort to Cohen's was announced earlier this month by the developers of advanced Java-based multi-platform BitTorrent client software Azuerus.